Influence of indigenous inputs on the properties of old alluvial soil in a mustard cropping system

Field experiments were conducted at the Crop Research and Seed Multiplication Farm of Burdwan University, Burdwan, West Bengal, India, to evaluate the influence of integrated nutrient management on soil physicochemical properties in a mustard (Brassica campestris cv. ‘B9’) cropping system. The experiment was conducted during the winter seasons of 2011–2012 and 2012–2013 in old alluvial soil (pH 6–7). Seven different doses of biofertilizers (Azotobacter and phosphate solubilizing bacteria (PSB)), vermicomposts, organic (cow dung), and chemical fertilizers were applied on mustard in both the experimental seasons. The results indicated an improvement in soil quality by increasing soil porosity and water holding capacity significantly, as well as gradual build-up of the soil micronutrient status after harvesting of the crop. Dual applications of biofertilizers and vermicomposts have contributed significantly to higher soil organic matter, available nitrogen (N), phosphorus (P), and potassium (K) contents as well as micronutrient availability of iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) and subsequently increased the soil health.     

An alternative eco-friendly approach for sustainable crop production with the use of indigenous inputs under old alluvial soil zone of Burdwan,West Bengal,India

Experiments were conducted on mustard (Brassica campestris cv.B₉) in an old alluvial soil zone of Crop Research and Seed Multiplication Farm, Burdwan University, Burdwan, West Bengal, India, during the winter seasons of 2011–2012 and 2012–2013. The aim was to evaluate the use of vermicompost prepared from municipality waste and Eichhornia mixture and its efficacy on crop growth and yield. Different combined doses of vermicompost, dried cow dung and chemical fertilizer along with Azotobacter and phosphate-solubilizing bacteria compared to full recommended dose of chemical NPK fertilizer (100:50:50) were used to develop an alternative farming technology for sustainable crop production and conservation of natural resources. The variety B₉ gave a significantly higher seed yield and oil content along with other growth and yield-contributing factors as well as being the most economically viable option against treatment T4 (i.e. 75% NPK + vermicompost at 2.5 tons per hectare) among all the treatments applied for the experiment and was found to be superior to other treatments in old alluvial soil of Burdwan, India. In both the experimental years, seed yield and oil content were found to be the best for the treatment T4 and was better than using chemical fertilizer.     

Effect of Integrated Nutrient Management on Soil Physical Properties and Crop Productivity under a Maize (Zea mays)–Mustard (Brassica campestris) Cropping Sequence in Acidic Soils of Northeast India

A five-year (2001/02–2006/07) field experiment was carried out on acidic clay loam soil classified as Typic Hapludalf with a maize–mustard crop sequence to study the effect of continuous application of nitrogen, phosphorus, and potassium (NPK) fertilizers alone and in combination with lime, farmyard manure (FYM), and biofertilizers on soil physical properties, soil organic carbon (SOC), soil microbial biomass carbon (SMBC), and crop yields on the hilly ecosystem of Meghalaya. Significant improvement in the soil physical conditions of the soil was observed under integrated application of organic manure and inorganic fertilizers. Addition of NPK fertilizers along with organic manure, lime, and biofertilizers increased soil organic carbon (SOC) content, aggregate stability, moisture-retention capacity, and infiltration rate of the soil while reducing bulk density. The SOC content under the treatment of 100% NPK + lime + biofertilizer + FYM was significantly greater (68.58%) than in control plots. Maize and mustard crop yields also significantly increased (4.73- and 21.09-folds, respectively) with continuous application of balanced inorganic (100% NPK) + lime + biofertilizer + FYM as compared to the control plots. However, crop yields drastically reduced under application of integrated nutrients without FYM as compared to the treatment with FYM application. Thus, the results suggest that integrated use of a balanced inorganic fertilizer in combination with lime and organic manure sustains a soil physical environment that is better for achieving higher crop productivity under intensive cropping systems in the hilly ecosystem of northeastern India.     

LEAF-MACRONUTRIENT STATUS AND FRUIT YIELD OF BIOFERTILIZED YELLOW PASSION FRUIT PLANTS

Biofertilizers instead of synthetic chemicals are known to improve plant growth through the supply of plant nutrients and they may help sustaining environmental health and soil productivity. An experiment was carried out to evaluate fruit yield and macronutrient foliar contents of yellow passion fruit plants (Passiflora edulis) as a function of biofertilizers and nitrogen-phosphorus-potassium (N-P-K) fertilizing in Brazil (2005–2007). The experimental design was randomized in blocks with treatments, which were distributed in a factorial arrangement (3 × 2) referring to biofertilizer application [without biofertilizer, simple biofertilizer and enriched biofertilizer] and mineral fertilizing with NPK (fertilized and non-fertilized), with three replications of nine plants. Nutritional status of yellow passion fruit is affected by biofertilizer. Simple biofertilizer promotes optimum supplies of phosphorus, calcium and sulfur, while enriched biofertilizer promotes optimum supplies of phosphorus, potassium, calcium and sulfur. Both biofertilizers stimulated fruit yield, with results above Brazilian average.     

Whole Forage Barley Crop Quality as Affected by Different Deficit Irrigation and Fertilizing Systems

Effects of organic, biological, and chemical fertilizers along with water-deficit regimes were investigated on forage barley in a field experiment during 2007–2008. Irrigation regimes were nonstressed (NS), moderately stressed (MS), and severely stressed (SS) and fertilizer treatments were no fertilizer (NF), phosphorus and nitrogen biofertilizers (BF), chemical fertilizer (CF), vermicompost (VC), chemical fertilizer + vermicompost (CV), and chemical fertilizer + biofertilizer (CB). Water stress reduced leaf/stem ratio and dry-matter digestibility (DMD), but increased crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF). However, the effect of water deficit on DMD, ash, and NDF depended on the fertilizer treatment. In BF and CV, the barley forage had the greatest DMD and least ash and NDF under water-deficit conditions. The integrated fertilizing systems are more reliable than conventional systems to produce high-quality forage barley in arid environments with late water stress or water deficit irrigation system.     

Nitrogen‐enriched compost application combined with plant growth‐promoting rhizobacteria (PGPR) improves seed quality and nutrient use efficiency of sunflower

Ecological benefits associated with plant growth‐promoting rhizobacteria (PGPR) inoculants offer a promising integrated nutrient management option to counteract plant nitrogen (N) deficiency. We performed field experiments to evaluate the effect of integrated N fertilizer regime involving chemical N fertilizer (CNF) and N‐enriched compost (NEC), either alone or combined with selected PGPR (Pseudomonas aeruginosa ) on sunflower seed quality, N use efficiency (NUE) and soil fertility during 2014–2015. We found that integrated N biofertilizer application resulted in significantly higher seed oil concentration, fatty acid composition, and harvest index in both cropping years. Greater effects on N yield efficiency (NYE), N use efficiency (NUE), N physiological efficiency (NPE), and photosynthetic N use efficiency (PNUE) were recorded in nitrogen‐enriched compost+PGPR inoculant (NECPI) treatment followed by chemical N fertilizer+PGPR inoculant (CNFPI) treatment. Statistically significant differences were observed in linoleic and linolenic acid, NYE, and NUE for treatment × year interaction, thus, suggesting that the integrated N biofertilizer approach facilitates the efficient N use by sunflower for improving yield and seed quality. Moreover, we also found considerable enhancement of soil N fertility after two consecutive cropping years of sunflower. The enhancement of seed quality, N use efficiencies, and soil N fertility through integrated N biofertilizer application emphasizes the importance of balanced crop N nutrition, ensuring sufficient N supply to sunflower with adequate N balance in soil for the next crop. Overall, combination of PGPR with NEC amendment may optimize N uptake efficiency and reduce N fertilizer losses, which is necessarily required for the sustainable sunflower production.     

Effect of Long-Term Integrated Nutrient Management (INM) Practices on Soil Nutrients Availability and Enzymatic Activity under Acidic Inceptisol of North-Eastern Region of India

ABSTRACT

Soil acidity is one of the main limitations for optimal use of land resources for better crop production. And, long-term fertilization experiments found to be helpful in increasing the nutrient supply in these acidic soils. Keeping this in view, a field experiment on rice was carried out by applying biofertilizers and enriched compost in an acidic Inceptisol of Assam over 10 successive years (2006–15) to examine its effects on nutrient availability and soil enzymatic activity. This experiment had five treatments viz. absolute control (T₁), 100% recommended doses (RD) of inorganic NPK (T₂), 50% RD of inorganic NP + 100% K +biofertilizers (T₃), 50% RD of inorganic NP + 100% K +1 tonne enriched compost ha^?1 (T₄) and 25% RD of inorganic NP + 100% K +2 tonnes enriched compost ha^?1 (T₅) under randomized block design with four replications. After completing 10 years of experiment, it was observed that integrated use of enriched compost and biofertilizers with reduced doses of inorganic fertilizers enhanced the soil enzymatic activity as well as nutrient availability in rice grown in acidic clay loam soils of Assam. Application of biofertilizers and enriched compost had positive impact on plant accessible nitrogen, phosphorus and potassium in soil as compared to inorganic fertilizers. Also soil organic matter content increased considerably by these treatment. Integrated nutrient management practice in rice had also significantly enhanced the dehydrogenase, fluorescein diacetate and phospho-monoesterase activity in soil.     

Effect of different composts on growth and nitrogen composition of Chinese mustard in an acid red soil

Abstract

A pot experiment was conducted to assess the effect of different kinds of composts on the growth and nitrogen (N) composition of Chinese mustard in acid red soil. There were six treatments including a lime‐chemical fertilizer treatment and a control plot of conventional chemical fertilizer. The plants were harvested 37 days after transplanting and the growth and N composition of these plants were measured. The soil was also sampled, and selected chemical properties were determined after harvesting the plants. The results show that different composts affected the growth and soil chemical properties significantly. The pH, nitrate nitrogen (NO₃‐N), ammonium N (NH₄‐N), electrical conductivity (EC), and 1 N ammonium acetate exchangeable potassium (K), calcium (Ca), magnesium (Mg), aluminum (Al), manganese (Mn), and iron (Fe) were all significantly affected by the compost treatment. The growth of plants in the control treatment was significantly lower than that of the compost‐treated and lime‐treated plants, suggesting that the acid Oxisol is unfavorable for the growth of Chinese mustard. Some composts could increase the growth of Chinese mustard. The lime‐treated plants had higher concentrations of chlorophyll a and chlorophyll b than those of the compost‐treated plants. There were no significant differences between treatments in the concentrations of chlorophyll a and chlorophyll b, however, there was a close correlation between the total chlorophyll concentrations and the shoot yield of the plants. The NO₃‐N, soluble reduced N, and insoluble N concentrations in leaf blades and petioles of Chinese mustard varied significantly according to the compost applied. The hog dung compost B could adequately supply nutrients especially N for plant growth and caused little NO₃‐N accumulation in plant tissues.     

Improvement in growth and alkaloid content of Rauwolfia serpentina on application of organic matrix entrapped biofertilizers (Azotobacter chroococcum,Azospirillum brasilense and Pseudomonas putida)

The field experiment was conducted to study the effect of conventional chemical fertilizer (urea),conventional biofertilizers (charcoal based) and organic matrix entrapped biofertilizer; (OMEB: a consortium of Azotobacter chroococcum, Azospirillum brasilense and Pseudomnas putida entrapped with clay soil, neem leaves, and cow dung in ratio of 1:1:1 and 15% saresh (plant gum of Acacia sp.) in various doses on growth parameters of Rauwolfia serpentina in terms of root length, shoot length, number of leaves, number of roots and fresh and dry weight of roots and shoots. Replacement of conventional chemical fertilizer by the consortium of biofertilizers (un-entrapped) increased plant growth in a dose dependent manner up to triple dose of the recommended dose (RD) of biofertilizers (1.80 kg ha-1). This increase in plant growth was not up to the level which appeared in the application of RD of urea. Entrapment of the same biofertilizers in an organic matrix mentioned above enhanced the plant growth similar to that observed for urea. The percentage increase of 9.57 and 7.54 in fresh weight (FW) and 11.93 and 11.12% in dry weight (DW) of shoot and 17.94 and 37.87% in FW of roots and 31.90 and 50.08% in DW of roots were recorded in 75 days old plant by the application of OMEB- triple dose over the conventional biofertilizers triple dose and recommended dose of urea. Conventional biofertilizers enhanced the availability of nitrate, nitrite and phosphate in the roots and leaves of the plant over application of urea as well as conventional biofertilizers. This formulation also increased alkaloid contents of in the roots of this plant. Microbial population of soil was also improved indicating enhanced soil fertility with application of OMEB. The results indicate that replacement of chemical fertilizers with microbial biofertilizers is possible with application of higher dose of biofertilizers entrapped into the organic matrix for the cultivation of medicinal plants like R. serpentina.     

Effects of Coal- Derived Humic Substance on Some Soil Properties and Bread Wheat Yield

In the present study, gyttja and its humic–fulvic concentrate were applied to soil either alone or in combination with a chemical fertilizer in a 2-year replicated field experiment with continuous bread wheat cropping during two seasons between 2005 and 2007 in Cukurova, Adana, Turkey. The changes in soil organic matter (SOM) characteristics and available micronutrient status were monitored by soil samplings performed immediately after the harvest in the 2005 and 2006 cropping seasons. The results showed that single and combined applications of humic substances with different types and doses showed different inclinations on selected soil characteristics in consecutive cropping seasons. The levels of SOM, available phosphorus, and grain yield significantly increased under different humic treatments in the first year of the experiment. However, humic substances added to the soil did not affect selected soil parameters and macro- and micronutrient status in the second year of the experiment.     

Changes in Biological Properties in Soil Amended with Rock Phosphate and Waste Mica Enriched Compost using Biological Amendments and Chemical Fertilizers Under Wheat-Soybean Rotation

The main aim of this research work is to prepare an enriched compost using rice straw mixed with rock phosphate, waste mica and Aspergillus awamori and to study their effect on changes in microbial properties in soils with and without chemical fertilizers under wheat-soybean rotation. Data revealed that significant increase in microbial biomass carbon (MBC), dehydrogenase activity, phosphatase activities, and microbial biomass phosphorus (MBP) in soil were maintained in enriched compost than ordinary compost after both the crops. Significant increase in MBC, dehydrogenase activity, phosphatase activities, and MBP were found in surface soil. The maximum microbial activities were observed in the treatment receiving 50% recommended dose of fertilizer (RDF) + enriched compost at 5 t ha^?1 indicating that integrated use of chemical fertilizers and enriched compost significantly improved the biological properties of soil under wheat–soybean rotation thereby enhanced soil fertility and crop production.     

Poultry manure and banana waste are effective biofertilizer carriers for promoting plant growth and soil sustainability in banana crops

The aims of our study were to compare the effectiveness of poultry manure (PM) and banana waste (BW), with regard to their use as inoculant carriers of a bacterial consortium constituted by strains of Azospirillum, Azotobacter and P-solubiliser bacteria and to establish the most efficient dose of biofertilizer for a soil cultivated with banana (Musa paradisiaca AAA Simmonds), with respect to improving plant performance and soil physical and microbiological properties. Six months after planting, plant growth had increased with increase in dose of the biofertilizers applied. The biofertilizer prepared on BW enhanced the density of P-solubiliser bacteria, the concentrations of available P and foliar P to a greater extent than with the biofertilizer prepared on PM. The increases produced by the biofertilizer prepared on PM for the soil aggregate stability, enzymatic activities and the labile carbon fractions were highly correlated to the dose applied. Both biofertilizers can be considered potentially useful as inoculant carriers of PGPR but the usefulness of BW appears to be restricted to moderate doses of application (≤3%).     

Yield and quality of tomato grown under organic and conventional nutrient management

Nutrient management plays an important role in yield and quality of tomatoes. A field experiment was conducted during the years 2008–09 and 2009–10 to analyze the effect of organic and conventional sources of fertilizer on yield and quality of tomatoes in an acid lateritic soil of India. The organic sources of fertilizer were vermicompost (VC), crop residue (CR), vermiwash (VW) and biofertilizer (BF). The conventional input was chemical fertilizer (CF) applied at recommended dose of 100:80:60 kg ha^?1 of N:P₂O₅:K₂O for the tomato. The organic source VC was used to supply 100% N recommendation as single source or 50% N recommendation when combined with CF or organic sources. Maximum fruit yield was recorded when CF was applied at full dose, which was on a par with VC at full recommendation. A higher percentage of large-size fruits (>7 cm) was obtained in VC-based treatments compared with CF treatment. Vermicompost at full dose increased ascorbic acid, beta carotene, total soluble solids and color value compared with its half dose along with other organic sources (CR, BF). The potential exists to improve tomato fruit quality through a better nutrient management, whether it be conventional, organic or a combination of both.     

Carrier-based and liquid bioinoculants of Azotobacter and PSB saved chemical fertilizers in wheat (Triticum aestivum L.) and enhanced soil biological properties in Mollisols

Abstract

The increasing cost and imbalanced use of chemical fertilizers in wheat (Triticum aestivum L.) stressed the need to explore the potential of bioinoculants of Azotobacter and PSB for saving fertilizer N and P. Field experiments conducted for two years in a Mollisol at Pantnagar revealed maximum plant height, grain and straw yields and nutrient uptake by wheat with application of 100% NP. However, soil application of carrier-based biofertilizer at 10?kg?ha^?1 and liquid-based biofertilizers at 625 and 1250?mL?ha^?1 rates in combination of 75% NP were at par with 100% NP by recording significantly more mean plant height at different intervals, grain yield, by 10.9, 10.5 and 10.8%, and straw yield, by 8.6, 8.2 and 9.1%, over 75% NP, respectively. These treatments also accumulated significantly more N, P and K in plant at different age and; grain and straw. An application of liquid biofertilizer at 1250?mL?ha^?1 with 75% NP gave maximum population of Azotobacter and PSB, microbial biomass C and activities of acid and alkaline phosphatase in soil at different crop age. The carrier and liquid formulations of the biofertilizers were comparable in their performance. Irrespective of formulation and doses, application of biofertilizers in soil was found better than seed treatment for different recorded parameters. An application of 625?mL?ha^?1 liquid biofertilizers in soil with 75% NP was found optimum for the growth, yield and nutrients uptake and soil biological properties.     

Effects of Different Types of Composts on Soil Characteristics and Morphological Traits of Two Dry Rangeland Species

Today, environmental protection and safe crop production are very important. The management of soil elements by compost is considered as important for sustainable agriculture. The mode of action of the composts is very different between various plant species. To evaluate the effects of different composts on soil structural and chemical properties and on morphological traits of two dry rangeland species (atriplex; Atriplex lentiformis and mesquite; Prosopos juliflora), a study was conducted in Fars Province of Iran during the year 2010. The study was a factorial experiment based on a randomized complete block design with three replications. Treatments included compost types: solid (SC) and liquid compost or compost tea (LC), solid-liquid mixture (XSL) and control (Con; non used compost) as the first factor, and two pasture plant species as the second factor. The results showed that the compost application had significant and positive effects on morphological traits such as plant height, stem diameter, plant volume, crown length, width, and area, and caused 15, 51.18, 70.67, 34.18, 18.35, and 64.94% increase on these morphological traits, respectively. Although soil acidity was not significantly affected by compost and species, the effects of compost were significant on organic matter percentage, soil phosphorous, and potassium contents. Soil nitrogen percentage was affected by both species and compost. Compost application caused a decrease in the amount of sodium compared with the control. Overall, the results of this study suggested that within the compost types, liquid compost was an advisable biofertilizer in a similar climate. Furthermore, the LC and the XSL are recommended for improving the morphological traits and the soil characteristics, respectively.     

Productivity,Quality and Soil Health as Influenced by Organic,Inorganic and Biofertilizer on Field Pea in Eastern Himalaya

A field experiment was conducted during two consecutive years of 2010–2011 and 2011–2012 to study the effect of biofertilizers in conjunction with organic and inorganic sources of nutrient management on productivity, quality and soil health on field pea at ICAR RC for NEH Region, Nagaland Centre Jharnapani, Nagaland, India. The experiment was laid out in split plot design with five nutrient sources in main plots and four treatment of biofertilizers with zinc in sub plots. Results indicated that the application of 100% recommended dose of fertilizer (RDF) through inorganic + 50% recommended dose of nitrogen (RDN) through vermicompost significantly improved root nitrogen (N) content, cation exchange capacity (CEC) of roots, NA activates, seed yield (1153 and 1262 kg ha^?1), straw yield (2182 and 2332 kg ha^?1) in the year of 2010–2011 and 2011–2012, respectively. Nutrients (N, P, K, S and Zn) uptake by seed and straw, protein content, protein harvest, soil organic carbon (SOC), available N, P, K, S, Zn and economics significantly higher with 100% RDF through inorganic + 50% RDN through vermicompost during both the years. Seed inoculation with biofertilizers along with 5 kg Zn ha^?1 markedly enhanced the root N content, CEC of roots, nitrogenase activities (NA), seed yield (1080 and 1193 kg ha^?1), straw yield (1978 and 2128 kg ha^?1), nutrients [N, phosphorus (P), potassium (K), sulfur (S) and zinc (Zn)] uptake, soil organic carbon (SOC) (%), and available N, P, K, S, and Zn of pea in both the years, respectively. These sources also give more income and benefit cost ratio per rupees invested.     

Soil microbial biomass phosphorus as an indicator of phosphorus availability in a Gleyic Andosol

Abstract

The relationship between plant phosphorus (P) uptake and soil microbial biomass phosphorus (biomass P) or available phosphorus (Truog P) was estimated in a Gleyic Andosol in Sapporo, Hokkaido, in a 4-year field trial (2004–2007). Every year, the soil was treated in duplicate (each plot 36?m²) or triplicate (each plot 24?m²) with chemical fertilizer, cow manure compost or sewage sludge compost, and then kidney beans (Phaseolus vulgaris) were planted. Pooled data of the shoot content of P at harvest over the 4?years was significantly correlated with biomass P determined 1?month after the application of fertilizer (P?<?0.01). A multivariate analysis revealed that the grain yield was significantly positively correlated with the shoot content of P (P?<?0.01) and significantly negatively correlated with the shoot content of calcium (P?<?0.05), but not correlated with the shoot content of either nitrogen or potassium. These results suggest that P is the most limiting element to affect the productivity of kidney bean plants in this trial and that biomass P is an important P source that explains the differences in P availability among soil amendments. Biomass P is a better indicator of P availability for kidney beans grown in Gleyic Andosols compared with Truog P, which is widely used in Japan.     

Long-term effects of compost amendment of soil on functional and structural diversity and microbial activity

We studied the effects of applying different composts (urban organic waste, green waste, manure and sewage sludge), mineral fertilizer and compost plus mineral fertilizer on chemical, biological and soil microbiological parameters over a 12‐year period. The organic C and total N levels in soils were increased by all compost and compost + N treatments. Microbial biomass C was significantly (P ≤ 0.05) increased for some compost treatments. In addition, basal respiration and the metabolic quotient (qCO₂) were significantly higher in all soils that had received sewage sludge compost. The Shannon diversity index (H), based on community level physiological profiling, showed a higher consumption of carbon sources in soils treated with compost and compost + N compared with the control. The utilization of different guilds of carbon sources varied amongst the treatments (compost, compost + N or mineral fertilizer). Cluster analysis of polymerase chain reaction‐denaturing gradient gel electrophoresis patterns showed two major clusters, the first containing the mineral fertilization and compost treatments, and the second, the composts + N treatments. No differences in bacterial community structure could be determined between the different types of compost. However, the results suggest that long‐term compost treatments do have effects on the soil biota. The results indicate that the effects on the qCO₂ may be due to shifts in community composition. In this study, it was not possible to distinguish with certainty between the effects of different composts except for compost derived from sewage sludge.     

Poultry Manure and Nitrogen–Phosphorus–Potassium Fertilizer Application and Their Residual Effects on Soil Physical Properties in Two Distinct Ecological Zones of Central Southern Nigeria

Poultry manure and nitrogen–phosphorus–potassium (N–P–K) fertilizer application and their residual effects on soil physical properties were investigated with soils drawn from two distinct ecological zones, Agbede (derived savanna) and Obadan (forest), of Edo State of southern Nigeria in 2005 and 2006 rainy seasons. The treatments consisted of three levels of poultry manure (0, 4, and 6 tons/PM/ha) and four levels of NPK 15:15:15 fertilizer (0, 50, 100, and 150 kg NPK ha^?1), which were combined factorially, arranged in a randomized complete block design, and replicated three times. Poultry manure, combined application of poultry manure and NPK fertilizer in 2005, and their residual effects in 2006 gave greater degree of saturation and soil moisture content and lower soil bulk density in both locations but were significantly better in the Obadan location in 2006. The lowest bulk densities of 1.16 and 1.15g cm² were obtained with the application of 6 tons PM ha^?1 + 50 kg NPK ha^?1 in Obadan soils in 2005 and 2006, respectively. Water-stable aggregate, porosity, void ratio, and air-filled porosity were greater in 2006 due to the residual effects of poultry manure and its combined application with NPK fertilizer than in 2005. In contrast, fertilizer application alone reduced void ratio, porosity, and air-filled porosity of the soils.     

Growth,Nutritional, and Yield Parameters of Wetland Rice as Influenced by Microbial Consortia Under Controlled Conditions

A pot culture experiment was undertaken under controlled conditions in the National Phytotron Facility to investigate the interactive effect of microbial inoculants—blue-green algae (BGA), Azospirillum, phosphate-solubilizing bacterium (PSB) Pseudomonas striata, vesicular-arbuscular mycorrhizal fungus (VAMF), and Azolla, individually and in combination with chemical fertilizers and/rock phosphate on the wetland rice (Oryza sativa L.) cultivar ‘PNR 381’. The microbial inoculants—BGA, PSB, VAMF, and Azospirillum—positively interacted with one another, resulting in significant improvement in yield and nutritional parameters. Application of biofertilizers also substantially improved soil (peat) fertility status by increasing the nitrogen (N), phosphorous (P), and organic carbon content. The biofertilizer combination BGA + PSB + VAMF + Azospirillum was best for improved growth and yield traits, nutritional status of rice, and sustained soil (peat) fertility. Azolla, which is a highly competitive organism, suppressed the growth of the other four inoculants. The inclusion of VAMF and PSB was observed to significantly improve the zinc nutrition of the paddy and the P utilization of the applied rock phosphate. A basal dose of nitrogenous fertilizer was essential for deriving maximum benefits from applied inoculants, thereby underlying the supplementary/complementary role of biofertilizers in efficient nutrient management in agriculture.